Denestable container cover



June 10, 1969 E. L. SMITH ET AL 3,448,888

' DENESTABLE CONTAINER COVER Filed March '15. 1968 Sheet of 2 INVENTORSE.L.SM ITH s.o.co| u E A TTORNEKS June 10, 1969 E. L. SMITH ETDENESTABLE CONTAINER COVER Sheet Filed March 15. 1968 FIG. 5

FIG. 4

INVENTORS E.L.SM|TH S. D.COLLIE Y mda 6 7 I l I a l F F 1 1 I y I 1.KUILII. \VI\|LJ.\I\I\IL 3,448,888 DENESTABLE CONTAINER COVER Ernest L.Smith and Stafford D. Collie, Kansas City, Mo.,

assignors to Phillips Petroleum Company, a corporation of Delaware FiledMar. 15, 1968, Ser. No. 713,434 Int. Cl. B65d 43/10, 21/04, 41/18 US.Cl. 220-60 10 Claims ABSTRACT OF THE DISCLOSURE A cover, for corneredcontainers having an inverted U-shaped rim with a lip extendingoutwardly from the bottom of the outer leg of the U, is provided with atop surface member and a depending rim flange. The rim flange hasoutwardly extending indentations therein, except at the corners, toreceive the container lip. Vertical walled depressed areas are providedin the top surface wall to serve as stacking lugs.

This application relates to a denestable, flexible, thermoformed cover.

Thermoformed plastic containers and covers of the type disclosed in I.O. Motsenbocker, US. 3,320,993 issued May 23, 1967, have becomeincreasingly useful for packaging various products, It is the generalpractice to ship empty containers of this type in a nested condition andsimilarly to separately ship the covers in nested stacks. In the pastthe outwardly extending indentations in the depending rim flange of thecover have served as stacking shoulders. However, difficulties have beenencountered when a vertical eccentric force is applied to a stack ofcovers, resulting in the outward indentation in a corner of one coversnapping over the outward indentation in the corner of the next lowercover in the stack and locking in this position. The relative stiffnessof the corner structures render such a stack of over-snapped covers verydiflicult to denest. These difliculties are particularly evident incovers and containers thermoformed from thermoplastic materials having asmall shrinkage factor, for example acrylonitrile-butadiene-styrene,polystyrene and the like. The low shrinkage factor limits the maximumamount of undercut in the mold to form the outwardly extendingindentations and thus the width of the stacking shoulder.

It has now been discovered that the foregoing difliculties can beminimized or avoided by eliminating the outwardly extending indentationsin the corner areas of the covers and providing depressed areas in thetop surface of the covers, the depressed areas having substantiallyvertical side walls so that the distance across the lower surface of thebottom of the depressed area is greater than the corresponding distanceacross the opening at the top of the depressed area, the verticaldistance between the lower surface of the bottom of each depressed areaand the upper surface of the top surface adjacent the depressed areabeing at least as great as the distance between the lower surface of anyother portion of the cover to the upper surface of another portion ofthe cover which said other portion in a second cover resting on thefirst cover would be directly above said another portion of the firstcover.

Accordingly, it is an object of the invention to provide a new andimproved flexible, thermoformed plastic cover which is denestable from astack thereof. Another object of the invention is to minimize oreliminate the locking of the depending flange of one cover to thedepending flange of another cover. Another object of the invention is tostrengthen a stack of nestable covers.

Other objects, aspects and advantages of the invention United StatesPatent 3,448,888 Patented June 10, 1969 ICC will be apparent from astudy of the specification, the drawings and the appended claims to theinvention.

In the drawings, FIGURE 1 is a perspective view of a cover in accordancewith one embodiment of the invention, FIGURE 2 is a perspective view ofa container with which the cover of the invention can be utilized,FIGURE 3 is a plan view of the cover of FIGURE 1 attached to thecontainer of FIGURE 2, FIGURE 4 is a partial crosssectional view alongline 4-4 of the cover and container of FIGURE 3, FIGURE 5 is a partialcross-sectional view along line 55 of the cover and container of FIG-URE 3, FIGURE 6 is a partial cross-sectional view of a stack of thecovers of FIGUREI taken along a line represented by line 66 in FIGURE 1,and FIGURE 7 is a plan view of a cover in accordance with anotherembodiment of the invention.

Referring now to the drawings and to FIGURE 2 in particular, container11 is a thermoformed plastic container having a substantiall rectangularhorizontal cross section, with a bottom member 12, and upstanding wallmembers 13, 14, 15 and 16 connected by corners 17, 18, 19 and 21. A rim22 extends outwardly in a substantially horizontal direction from theupper end of wall members 13, 14, 15 and 16 and corners 17, 18, 19 and21, and then downwardly, terminating with an outwardly extending lip 23.

As illustrated in FIGURES 1 and 3, the flexible, thermoformed plasticcover 31 has a top surface member 32 adapted to cover the opening ormouth at the upper end of container 11 with side edges corresponding innumber and horizontal length to the upstanding walls of container 11.Cover 31 has flange members 33, 34, 35 and 36 connected to the topsurface member 32 along the side edges thereof and extending downwardlytherefrom. The adjacent flange members 33, 34, 35 and 36 are connectcdby downwardly extending corner members 37, 38, 39 and 40 to form adepending flange continuously around the periphery of top surface member32. Flange members 33, 34, 35 and 36 are provided with outwardlyextending substantially horizontal indentations 41, 42, 43 and 44,respectively, adapted to engage lip 23 of container 11 so that asnap-action arrangement is provided to releasably hold cover 31 oncontainer 11. Indentations 41, 42, 43 and 44 are positioned within therespective flange members and do not extend into corner members 37, 38,39 and 40, the latter being substantially straight between the top andbottom edges thereof, as illustraed in FIGURE 4. A lip 45 can beprovided around the lower periphery of the flange members 33, 34, 35 and36 and corner members 37, 38, 39 and 40 extending substantiallyhorizontally outwardly to aid in manually grasping the edge of a cover31 for removal from a container 11. A shallow depression 46 can beprovided in top surface member 32 to receive and protect a label 47 orother indicia. Columnar projections 51, 52, 53 and 54 are positioned indepression 46 so as to be covered by label 47. Columnar projections 51,52, 53 and 54 extend downwardly from the adjacent surface of depression46 to form depressed areas which serve as stacking members. Depressedareas 51, 52, 53 and 54 are positioned adjacent corner members 37, 38,39 and 40, respectively, to provide greater stability in a stack ofcovers. The vertical distance X in FIGURE 6, between the lower surfaceof the bottom of projections 51, 52, 53 and 54 and the upper surface ofthe adjacent portion of top surface member 32 in the depression 46 is atleast as great as the distance between the lower surface of any otherportion of the cover 31 (for example, lip 45) to the upper surface ofanother portion of the cover positioned thereabove (for example, theupper surface of indentation 42), which latter lower surface in a stackof covers would rest on the latter upper surface of the next lowercover.

3 In the parenthetical example, this latter distance can be the distanceY in FIGURE 6. In a presently preferred embodiment of the invention thedistances X and Y are equal and the upper surface of each ofindentations 41, 42, 43 and 44 is substantially horizontal so thatprojections 51, 52, 53 and 54 and indentations 41, 42, 43 and 44 serveas spaced stacking members to provide vertical strength to a stack ofcovers as well as maintaining the covers at the desired spacing.

While depressed areas 51, 52, 53 and 54 have been illustrated asindividual columnar projections having substantially circular horizontalcross sections, other configurations can be utilized. For example, thedepressed areas can be interconnected as illustrated by cover 70 inFIGURE 7 wherein elements corresponding to the cover of FIGURES l and3-6 have been designated with the respective reference numeral. Adepressed area 71 in the form of two intersecting channels extends topoints adjacent each of corners 37, 38, 39 and 40. Again, depressed area71 has substantially vertical side walls and a stacking height in themanner of the depressed areas 51, 52, 53 and 54. Additional depressedareas can be employed in other areas of top surface member 32.

While container 11 and covers 31 and 70 have been illustrated as havingsubstantially rectangular horizontal cross sections, otherconfigurations such as triangular, pentagonal, hexagonal, and the likecan be utilized.

Reasonable variations and modifications are possible within the scope ofthe foregoing disclosure, the drawings, and the appended claims to theinvention.

We claim:

1. In a flexible thermoplastic cover for a container having at leastthree upstanding walls, adjacent upstanding walls being joined bycorners, a rim extending outwardly from the upper end of each of saidupstanding walls and then downwardly and terminating with an outwardlyextending lip; said cover comprising a top surface member adapted tocover the opening in the upper end of said container and having aplurality of side edges corresponding in number and horizontal length tosaid upstanding Walls of said container, a plurality of flange memberscorresponding in number to said plurality of side edges, each of saidflange members depending downwardly from a respective one of said sideedges, adjacent flange members being connected by downwardly extendingcorner members to form a depending flange continuously around theperiphery of said top surface mem ber, the improvement comprising eachof said flange members having an outwardly directed indentation thereinadapted to engage said outwardly extending lip of said container so thata snap action arrangement is provided between said cover and saidcontainer, each of said indentations terminating short of the adjacentcorner members, said corner members being substantially straight betweenthe top and bottom edges thereof, a depressed area in said top surfacemember adjacent each of said corner members, each depressed area havingsubstantially vertical side walls so that the distance across the lowersurface of the bottom of the depressed area is greater than thecorresponding distance across the opening at the top of the depressedarea, the vertical distance between the lower surface of the bottom ofeach depressed area and the upper surface of said top surface memberadjacent the depressed area being at least as great as the distancebetween the lower surface of any other portion of the cover to the uppersurface of another portion of the cover which said other portion in asecond cover resting on the first cover would be directly above saidanother portion of the first cover.

2. A cover in accordance with claim 1 wherein said container and saidcover are substantially rectangularly shaped.

3. A cover in accordance with claim 1 wherein the depressed areas areinterconnected with one another.

4. A cover in accordance with claim 1 wherein each depressed area is inthe form of a columnar projection.

5. A cover in accordance with claim 1 wherein the distance from theupper surface of said indentations to the lower surface of said flangemembers is equal to the height of said depressed areas.

6. A cover in accordance with claim 1 wherein said top surface memberhas a shallow depression to receive a label.

7. A cover in accordance with claim 6 wherein said depressed areas arelocated within said shallow depression.

8. A cover in accordance with claim 7 further comprising a labelpositioned in said shallow depression and covering the openings of saiddepressed areas.

9. A cover in accordance with claim 8 wherein said container and saidcover are substantially rectangularly shaped and each depressed area isin the form of a columnar projection extending downwardly.

10. A cover in accordance with claim 9 wherein said columnar projectionshave substantially circular horizontal cross sections.

References Cited UNITED STATES PATENTS 3,320,993 5/1967 Motsenbocker22060 XR 3,321,104 5/1967 Edwards 22097 3,351,227 11/1967 Collie 220-GEORGE T. HALL, Primar Examiner.

US. 01. X.R. .5; 220+97

